---
id: CVE-2026-89530
title: 'svcrdma: Reject inline replies that overflow the pull-up buffer'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  svcrdma: Reject inline replies that overflow the pull-up buffer

  An RPC-over-RDMA client can request a reply, such as an NFS READ
  payload, without providing a Write lis…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-787
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf <
    b73011049dbe909f73fd9620d94ef1757d7af2eb
  - >-
    Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf <
    8068358f445a11296328ffa7c524701596814a17
  - >-
    Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf <
    fcd91b9957462d398792201c239dffaeff1cc8b2
  - >-
    Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf <
    1949dd1576f7a8aa161b1330c6125df9d53046d5
  - >-
    Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf <
    8ec60eb51fae37cd3d334ff26e4a7d6fb21ff7cf
  - >-
    Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf <
    0fbe20dfe74b783d255bf389a6ea77aa25dc7860
  - Linux 9b65b18f817d9ada2bf67351f24bdcce6789a0bb
  - Linux d564356e1919d1178568c19af410cfc1a9076663
  - Linux >= 4.19.22 < 4.20
  - Linux >= 4.20.9 < 4.21
  - Linux 5.0
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T19:23:07.762867Z'
published: '2026-09-11'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:32:01.396Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89530'
references:
  - url: 'https://git.kernel.org/stable/c/b73011049dbe909f73fd9620d94ef1757d7af2eb'
  - url: 'https://git.kernel.org/stable/c/8068358f445a11296328ffa7c524701596814a17'
  - url: 'https://git.kernel.org/stable/c/fcd91b9957462d398792201c239dffaeff1cc8b2'
  - url: 'https://git.kernel.org/stable/c/1949dd1576f7a8aa161b1330c6125df9d53046d5'
  - url: 'https://git.kernel.org/stable/c/8ec60eb51fae37cd3d334ff26e4a7d6fb21ff7cf'
  - url: 'https://git.kernel.org/stable/c/0fbe20dfe74b783d255bf389a6ea77aa25dc7860'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89530.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89530'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532218'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89530'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89530'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89530.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00491
epssPercentile: 0.42339
scores:
  cna: 9.8
  vendor: 7
ingestedAt: '2026-09-14T15:23:07.474Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

svcrdma: Reject inline replies that overflow the pull-up buffer

An RPC-over-RDMA client can request a reply, such as an NFS READ
payload, without providing a Write list or a Reply chunk to carry
it. When such a reply needs more scatter/gather entries than the
device's Send Queue supports, svc_rdma_pull_up_needed() selects
pull-up and svc_rdma_pull_up_reply_msg() linearizes the whole
reply into sctxt->sc_xprt_buf. That buffer is only sc_max_req_size
bytes, while the reply on this path is bounded only by the client's
request, so svc_rdma_xb_linearize() copies past the end of the
buffer and corrupts adjacent slab memory. The oversized length is
then stored in sc_sges[0].length and posted, so the device also
reads beyond the mapped region.

The SGE-exhaustion branch is the only pull-up path that can exceed
the buffer: the threshold branch pulls up only replies smaller
than RPCRDMA_PULLUP_THRESH, and replies that fit the device's SGE
budget are sent directly without linearization. Make
svc_rdma_pull_up_needed() report -E2BIG when the reply it would
pull up cannot fit sc_max_req_size, and fail the request with
ERR_CHUNK as RFC 8166 Section 4.5.3 directs rather than dropping
the connection.

The helper no longer answers a simple yes/no question: it now
reports pull-up, no pull-up, or -E2BIG for a reply too large to
linearize. Rename svc_rdma_pull_up_needed() to
svc_rdma_check_pull_up() so its name no longer implies a boolean
predicate.

## Affected

- `Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf < b73011049dbe909f73fd9620d94ef1757d7af2eb`
- `Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf < 8068358f445a11296328ffa7c524701596814a17`
- `Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf < fcd91b9957462d398792201c239dffaeff1cc8b2`
- `Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf < 1949dd1576f7a8aa161b1330c6125df9d53046d5`
- `Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf < 8ec60eb51fae37cd3d334ff26e4a7d6fb21ff7cf`
- `Linux >= e248aa7be86e8179f20ac0931774ecd746f3f5bf < 0fbe20dfe74b783d255bf389a6ea77aa25dc7860`
- `Linux 9b65b18f817d9ada2bf67351f24bdcce6789a0bb`
- `Linux d564356e1919d1178568c19af410cfc1a9076663`
- `Linux >= 4.19.22 < 4.20`
- `Linux >= 4.20.9 < 4.21`
- `Linux 5.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89530.json)